www.iaset.us editor@iaset.us OPTIMIZING THE EFFICIENCY OF WATCHDOG IDS IN MANETs USING SELFISHNESS INFORMATION AND BAYESIAN FILTERING VARSHA HIMTHANI 1 , PRASHANT HEMRAJANI 2 & SACHIN SHARMA 3 1 Department of Computer Science and Engineering, MAIET, Jaipur, Rajasthan, India 2 Department of Computer Science and Engineering, Poornima University, Jaipur, Rajasthan, India 3 Department of Computer Science and Engineering, RIET, Jaipur, Rajasthan, India ABSTRACT Mobile Ad-Hoc Networks (MANETs) are a new paradigm for wireless communication for mobile hosts. These Networks do not need the costly base stations as in wired networks or mobile switching centers in cellular wireless mobile networks. In such a network, each node acts as an end system as well as a relay node (or router). Routing protocol for MANETs are designed based on the assumption that all the participating nodes are fully cooperative. However, nodes may become selfish due to low battery life remaining. This selfishness is a characteristic property of any node which is provided by the device manufacturer so as to maximize the node life before being fail due to exhausted battery. Depending upon the probability distribution of mean number of packets to be transferred by any node in the network, one can calculate the average life of a node before it attains selfish behavior. Also, there is always a scope of intruder attacking and harming the usual functioning of the Network, which may cause a node to perform maliciously thereby forwarding packets in unusual way to the unauthorized. The watchdog is a well-known sensor usually adopted for detecting black-holes in such networks, but typical watchdogs are characterized by a relatively high number of false positive and negative cases, which can affect the effectiveness and efficiency to deal with intrusions. This paper proposes a novel approach for detecting selfish node in mobile P2P networks by using Bayesian Filtering and an estimation of the mean time to get selfish for any node. KEYWORDS: MANET, Selfishness I. INTRODUCTION Mobile Ad hoc NET works (MANETs), are distributed systems composed by wireless mobile nodes that can freely and dynamically self-organize into arbitrary and temporary topologies [1]. These networks have origins in military missions and recovery operations but, in the recent years, a wide range of possible civil applications emerged, e. g., vehicular networks (VANETs), a form of Peer to Peer [2] mobile networks used for communication among vehicles and between vehicles and roadside equipment. The main characteristic of such networks is that they allow different kinds of devices to easily interconnect in areas with no pre-existing communication infrastructure; there exist several protocol specifications, such as AODV [3], that aim to find routing paths between pairs of devices. These allow non-neighboring nodes to communicate by using intermediate nodes as relays. But the majority of these protocols assume a friendly, reliable and cooperative environment. Therefore, a single malicious node can easily prevent a mobile network from working and therefore the emerging need for research focused on the provision of practical proposals for securing them. There have been numerous contributions to secure wireless networks, including key management, secure routing, International Journal of Computer Science and Engineering (IJCSE) ISSN(P): 2278-9960; ISSN(E): 2278-9979 Vol. 3, Issue 2, Mar 2014, 131-140 © IASET